Calif. voters retain death penalty despite costs

"The people of California sent a clear message that the death penalty should still be implemented for those who commit the most heinous and unthinkable crimes," said McGregor Scott, a former U.S. attorney for Sacramento who served as the opposition's co-chairman.

The measure's backers vastly outspent opponents $6.5 million to $1 million. Billionaires Nicholas Pritzker and Charles Feeney, through his philanthropic fund, each donated $1 million to the campaign for repeal. The American Civil Liberties Union contributed more than $700,000 and ran the campaign.

Federal and state judges have halted executions in the state since 2006 after ordering prison officials to develop new lethal injection procedures. Those lawsuits are still being litigated.